Electric Charge...

The number of electrons present in $$1\ C$$ of charge is ______.

Two charged particles having charges $$+25\mu C$$ and $$+50\mu C$$ are separated by a distance of $$8\ cm$$. The force acting on them is:

If two charges of $$1$$ coulomb each are placed $$1\ km$$ apart in vacuum, the force between them will be:

A charge of $$-30\mu C$$ is placed at $$50\ cm$$ from another charge of $$+25\mu C$$ in vacuum. The force between them is:

A point charge q produces an electric field of magnitude $$2\ N\ C^{-1}$$ at a point distance $$0.25\ m$$ from it. Find the value of charge.

Two charged particles having charge $$2\times 10^{-8}C$$ each are joined by an insulating string of length $$100\ cm$$. The system is kept on a horizontal table. Find the tension in the string.

Two particles having charges $$q_{1}$$ and $$q_{2}$$ when kept at a certain distance, exert a force F on each other. If the distance between the two charges is reduced to half then the force exerted on each other would be:

When a glass rod is rubbed with a piece of silk cloth the rod ?

The electrostatic force between two point charges $$q_{1}$$ and $$q_{2}$$ at separation 'r' is given by $$F = \dfrac {Kq_{1}q_{2}}{r^{2}}$$. The constant K:

A charged particle of mass $${m}_{1}$$ and charge $${q}_{1}$$ is revolving in a circle of radius $$r$$. Another charged particle of charge $${q}_{2}$$ and mass $${m}_{2}$$ is situated at the centre of the circle. If the velocity and time period of the revolving particle be $$v$$ and $$T$$ respectively, then :